Rock driling machine



I Aug- 31, 1965 R. J. ROBBINS ETAL 3,203,737

ROCK DRILLING MACHINE Filed March 18, 1965 5 Sheets-Sheet' 1 ll Il Ill I/ l s .jl

RICHARD J. ROBBINS DOUGLAS F. WINBERG JOHN GALGOCZY INVENTORS BY aww/Mju@ Aug. 31, 1965 R. .1. RoBBlNs ETAL 3,203,737

ROCK DRILLING MACHINE Filed March 18, 1963 5 Sheets-Sheet 2 RICHARD J. ROBBINS DOUGLAS F. WINBERG JOHN GALGOGZY INVENTOR.

BY J o 5024@ au( n Q N d' ATTORNEYS Aug. 31, 1965 R. J-RoBB|Ns ETAL 3,203,737

ROCK DRILLING MACHINE Filed March 18, 1963 5 Sheets-Sheet 3 RICHARD J. ROBBINS DOUGLAS F. WINBERG J OHN GALGOCZY INVENTOR.

BY WQLJJQ Aug 31, 1955 R. .1. RoBBlNs ETAL 3,203,737

ROCK DRILLING MACHINE Filed March 18, 1963 5 Sheets-Sheet 5 se e? 28 43A 46 l48 O Z V//l// la 40K 59 48 RiCHARD J. ROBBINS DOUGLAS F. WINBERG JOHN GALGOCZY INVENTOR.

MW smu United States Patent O I3,203,737 ROCK DRILLING MACHINE Richard J. Robbins, Seattle, Douglas F. Winberg, Bellevue, and John Galgoczy, Seattle, Wash., assignors to James S. Robbins & Associates, Inc., Seattle, Wash., a

corporation of Washington Filed Mar. 18, 1963, Ser. No. 265,812 16 Claims. (El. 299-31) This invention -relates to a boring machine, and more particularly to -that type of machine which bores tunnels of a relatively large diameter in a manner such that the machine itself travels progressively into the ground strata being bored as its large rotary head cuts a passage in the rock.

It is believed clarity in an understanding of the features to which the present application is di-rected will be advanced by here cursorily describing the general nature of this type of boring machine.

Such a machine provides a relatively large body portion having a diameter moderately less than the tunnel which is to be bored and desirably has a length greater than its diameter. There are mounted on the body of this machine a plurality of shoes arranged to be pressed outwardly so as to bear against the side wall of the tunnel. By retracting one pair of laterally extending diametrically opposed shoes from the tunnel wall, moving this pair of shoes forward, and then again pressing the latter shoes outwardly to take a new grip on the tunnel wall, the machine is able to walk along the length of the tunnel.

Mounted at the front of the body for rotary motion about the longitudinal axis of the machine is a large circular head having a front plate which faces the end wall of the tunnel from which the rock is being cut. On the front or working face of the cutting head are a plurality of cutters each having a freely rotating cutter wheel. Each of these wheels has a circumferential cutting edge, and the axis of rotation of each wheel passes through the axis of rotation of the head. Thus, as the machine pushes forward from its shoe mounts, the cutter wheels bear aganist the end face of the tunnel, and, by virtue of the rotary motion of the head roll against the rock so as to cut a plurality of circular kerfs in the rock face. As each cutter deepens its kerf by chipping away the adjacent rock, larger pieces of rock between proximate kerfs are caused to be broken away.

The large rotary head carries a plurality of Outrigger bucket members which are evenly spaced along the circumference of the head. As the head rotates, the bucket members follow a circular path along the circumference of the end wall of the tunnel and are arranged to scoop up the rock and other debris cut from the tunnel end wall and carry it to the top of the. machine. Here the buckets discharge the debris ont-o a rearwardly traveling conveyor which carries the debris to the rear of the machine.

With a fairly large number of cutters being used, and with the rather large resisting force of the rock against the kerf cutting action of even one such cutter, the total rearward thrust against the rotary head, vand the torque exerted on the head so as to resist the rotary motion thereof, are both of considerable magnitude. All these loads are transmitted by the head through the body of the machine to the gripping shoes and into the side wall of the tunnel.

One effect of the torque loads is to cause creeping of the machine about its longitudinal axis; i.e. the gradual slipping of the gripper shoes along the tunnel wall in a direction opposite to the rotation of the head.

Also there is the problem of maintaining the proper alignment of the machine in the tunnel, this being accomplished by manipulating the various support `and grip- 3,293,737 Patented Aug. 3l, 1965 ice ping shoes which press against the wall surrounding the machine. Since the rock formation, even in localized areas, can vary to a great extent, and since the rock may be stratied, or faults are sometimes present, both the resistance of the rock to the cutting action and the iirmness of support given to the shoes of the machine are subject to wide Variation. These factors contribute to the difficulty of steering the machine within the relatively close tolerances required for the proper formation of most tunnels.

One of the more significant limitations in prior art machines of this nature is with regard to the ability of such machines to steer during the cutting operation. For the prior art machines to make many of the movements necessary for proper steering, the gripper shoes must be retracted and moved to a new location with respect to the tunnel wall. However, for the machine to take the enormous loads created by the cutting action, the gripper shoes must be firmly planted against the tunnel wall throughout the cutting action. ln consequence thereof, with previous machines, when it is observed during a cutting operation that the machine is shifting, skewing, or tilting out of proper alignment, it is generally necessary to halt the cutting operation so that the shoes can be made to take a new grip on the tunnel wall, from which new gripping position the machine can then push forward on its corrected line of travel.

Another similar limitation in such prior art machines concerns the machines ability to cut a curved passageway. The usual prior art practice is to cut a plurality of straightline increments of tunnel length, which collectively approximate the desired curve line. When each such increment of tunnel length is completed, it has been necessary to stop the cutting action, shift the machine to a new line, land by means of the shoes take a new grip from which the machine pushes forward to bore another such straight line portion of tunnel.

For a machine of this nature to perform its tunnel boring function with optimum speed and eiciency dictates that the machine must be able to correct its alignment and to rotate itself back to level (because of the aforementioned sideways creeping) Without any necessity of moving the gripper shoes to a new position against the tunnel wall, inasmuch as such repositioning requires an interruption of the cutting operation. Also it is highly desirable to provide a machine so engineered that the same can bore an arcuate portion of tunnel without taking a new grip on the wall of the tunnel.

It is with the foregoing problems in mind that the structure of the present invention has been contr-ived, and it is thus a principal object of this invention to provide a machine which, without taking a new grip with its shoes on the tunnel wall, can move through an increment of forward travel and yet be able to pivot in any direction and move either laterally and/ or vertically simultaneously with such pivot and forward motion, so as to be able to steer and level itself and/or cut an arcuate passage without interrupting its boring operation as it moves along suchinc-rement of travel.

It is a further object to provide a machine of the type described which, while accomplishing the ends recited in the above object, is sufficiently rugged to withstand the Various torque and thrust loads exerted thereon in a manner to properly transmit such loads into the tunnel wall.

Other more particular objects and advantages of the invention will, with the foregoing, appear and be understood in the course of the following description andv claims, the invention consisting in the novel construction and in the adaptation and combination of parts hereinafter described and claimed.

In the accompanying drawings:

FIGURE 1 is a side elevational View of a boring machine embodying preferred teachings of our invention.

FiG. 2 is a fragmentary plan view of the gripper portion of said machine, drawn to an enlarged scale.

FIG. 3 is a transverse vertical sectional view on line 3 3 of FIG. 1, employing the same scale as that of FIG. 2.

FIG. 4 is a transverse vertical sectional View on line 4 41 of FIG. 2.

FIG. 5 is a side elevational view of the gripper portion of the machine.

FG. 6 is a longitudinal vertical sectional view of said gripper portion drawn on the jogged line 6 6 of FIG. 2.

IFIG. 7 is a fragmentary horizontal sectional view on line 7 7 of FIG. 4.

FIG. 8 is an enlarged-scale fragmentary longitudinal vertical sectional view detailing a portion of the apparatus which is also sectioned in FIG. 6.

FIG. 9 is a fragmentary longitudinal vertical sectional view drawn to an enlarged scale on line 9 9 of FIG. 2; and

FlG. l0 is a fragmentary horizontal sectional view drawn to an enlarged scale on line N l of FIG. 3.

Referring now to FIGURE l, the numeral 1t) generally designates the machines body portion, on which is mounted at the front thereof a large rotary head 11. Located immediately behind the head 11 and xed to the body 1G is a circumferential dust shield 12, the perimeter of which tits in close proximity to the side wall of the tunnel. This dust shield is flexible so that as the machine moves along the length of the tunnel the shield will yield when it encounters irregularities in the tunnels side wall.

Mounted about the periphery of the head 11 at circumferentially spaced intervals are a plurality of outrigger bucket members 13. Each of these buckets has its mouth 14 facing in a clockwise direction, as viewed from the front, and each bucket presents a forwardly projecting scoop 16 which serves to gather into said mouth the rock fragments and other debris removed from the end wall of the tunnel. Each of the buckets has an inner opening (not shown) and at the upper limit of travel registration is made between this opening and the forward end of a rearwardly traveling endless conveyor 17 so as to dump onto the latter. The conveyor extends along the top of the machine and discharges at the rear thereof.

Said rotary head 11 has a plurality of the aforementioned freely rotating cutters mounted on its front Face. Designated by 18, these cutters act in the afore-described manner to cut a respective circular kerf in the end wall of the tunnel. Several other cutters (for simplicity of illustration, not shown herein), and termed gauge cutters, are mounted on each of the bucket members 13. The gauge cutters are directed outwardly at various angles and operate to cut into the circumferential corner where the end and side walls ofthe tunnel meet.

To aid in guiding the machine, there is provided at the front of the body one downwardly and two laterally extending hydraulically operated shoes Ztl and 21, respectively, the latter two shoes being located one at each of the two sides at the approximate mid-height of the body 10. A suitable drive mechanism (not shown) rotates the head 11 by means of six electric motors (one of which is shown at 22), mounted three at each of the two sides of the body 19. A cab 23 for the operator is located near the rear of the machine, and at the extreme rear there is provided a crane Z4 to lift equipment to the top of the machine. Also provided at the rear of the machine is a downwardly extending hydraulically operated support foot 26. This foot is used to support the machine only while two gripper shoes (to be described more particularly hereinafter) are being shifted from one to another location relative to the tunnel side wall, and during boring oper: tions is lifted free ofthe tunnel floor.

Now proceeding to describe said gripper shoes, which function to support the machine during boring operations and are designated by 27j the same are opposingly mounted one at each of the two sides of the machine adjacent the mid-length of the latter. Extending laterally of the machine between these two shoes is the gripper mounting assembly, generally designated by 28. This assembly comprises three basic parts, namely, two open-center cross-heads 30, each of which carries a respective one of the two gripper Shoes 27, and a muff 31 producing slideways in each of its two ends for a respective one of the two cross-heads. This mounting assembly has two significant functioning characteristics: (l) the cross-heads can be forced outwardly from one another within the muff by pressure exerted from a set of four large hydraulic gripper jacks 32, which responsively presses the gripper shoes 27 rmly against the tunnel side wall, and (2), with the gripper shoes thus firmly planted, the muif 31 can Ibe shifted laterally, sliding on such localized crossheads, by means of a set of two smaller hydraulic steering jacks 33. This lateral shifting provides transverse steering for the machine.

A carriage 34 is supported on the muff with its mounting such that it can pivot in any direction, can also move vertically' relative to the axial line of the cross-heads, and can also move laterally through the expedient of shifting the mutf upon the localized cross-heads. Carriage 3. entirely surrounds the gripper mounting assembly 23, and has re-entrant openings top and bottom producing channels which function as upper and lower slide-ways. Received in these slide-ways is a related one of two paralleling jumbo bars 36A and 36B of boxsection configuration which serve as longitudinal principals for the main frame of the machine.

It should be here noted that the carriage 34 is not subjected to thrust loads exerted by the rock face on the rotary head 11. The carriage has as its functions to locate the main frame of the body and to resist torque loads created by the rotary cutting motion of the head 11. Thrust loads are passed from the head 11 through suitable bearing supports (not shown) into frame cheeks 19 located at the front portion of the body 10, and thence are carried directly to the gripping shoes through two pairs of hydraulic thrust jacks 37, one such pair being located on each of the two opposite sides of the machine.

For the vertical steering of the machine, there are provided four vertically disposed hydraulic jacks 38 located one at each of the four corners of the carriage and having their upper ends attached to out-jutting shoulder-pieces 39 of the carriage while the lower ends are attached to the muff.

Salient to the present invention is the precise manner in which the machine supports and moves itself, taking a purchase from the gripper shoes 27. Hence, it is believed that clarity in an understanding of the invention will be advanced by here reviewing the co-operating functions of the components which have been described thus far, and before proceeding with a detailed description of the several structures.

When the gripper shoes 27 are in retracted position (i.e. withdrawn from the side wall of the tunnel), the machine is supported by the three steering shoes 20-21-21 at the front of the machine, and by the rear foot 26. To move the gripper shoes 27 forwardly to a gripping position from which the machine can be advanced, and assuming that said shoes have been retracted from the wall, the four thrust jacks 37 are retracted so as to draw the gripper mounting assembly 28 and the carriage 34 forward on the machine frame. The slide mounting therefor is provided by the jumbo bars 36A and 36B. When the gripper shoes 27 have reached their forward limit of travel, the gripper jacks are extended to plant the gripper shoes rmly against the two lateral surfaces of the tunnel side wall.

With the shoes 27 now localized with respect to the side wall of the tunnel, the machine frame can be positioned so as to coincide with an axis which lies midway between the shoes normal to a transverse vertical plane occupied by the shoes or can be pointed up, down, to either side, or compoundings thereof. The horizontal steering jacks 33, by sliding the mud 31 and the attached carriage 34 in a lateral direction, causes the frame to be cocked to one side or the other. The vertical steering jacks 38, by extending or retracting the rear pair while operating the other pair in a lesser counter movement, causes the frame to be cocked up or down. The cutting head, being carried by the frame, shifts its rotary axis in concert with the shifting of the frame. It will perforce be understood that the several thrust jacks 37 are individually retracted or extended, as the change of `direction may prescribe, in concert with the activation of the steering jacks. Should any creeping of the shoes occur, counter activation of the pairs of steering jacks upon the two opposite sides of the carriage brings the carriage back to a level position as the latter responsively rolls about the longitudinal center of the beam 77 as an axis.

When the macihne frame has been properly located and it is desired to then proceed with the boring of the tunnel, straight-line boring is performed by extending the four thrust jacks 37 at equal rates, the thrust jacks pushing against the anchored gripper shoes 27 and responsively forcing the cutting head forwardly in the tunnel. As cutting proceeds the jumbo bars 36A and 36B of the machine frame walk along the slide-way which the carriage 34 provides.

lt will be understood that each of the vertical steering jacks 38, as well as said thrust jacks 37, may be operated independently of each other. Thus any compounding of lateral and vertical movements, within prescribed limits, may be obtained. The machine can be made to bore along an arcuate as well as a rectilineal path by extending the thrust jacks 37 at different rates and at the same time regulating the several steering jacks.

The front shoes 2i3-21-21 co-operate with the gripper shoes Z7 in supporting the machine. While the machine is performing its boring function, these shoes -21-21 have only sliding Contact with the tunnel wall, bearing against the wall only in the degree necessary to stabilize the rotary head.

Proceeding now to a more detailed description of the parts of the machine, each of the gripper shoes 27 has its outer surface 4t) vertically convex (see FIG. 4) to conform to the curved side wall of the tunnel, and to augment the gripping action presents a plurality of projecting radial spikes 4l. To compensate for irregularities in the side wall, each of the gripper shoes 27 is so attached to its related cross-head that it can pivot about both a longitudinal and a vertical axis. This is accomplished by providing upon the shoe a hub 43 serving with a block 44 as the two butt components of a hinge having its pin 46 disposed horizontally and longitudinal to the machine, and mounting said butt block 44 so that the same can itself rock about a vertical axis traversing the axial line of the hinge pin at a point central to the width of the gripper shoe. Such rocker mounting is provided by forming the hinge butt 42 with ianking semi-circular wheel sections 47 located normal to the hinge leaves and co-planar with top and bottom walls of the open-center cross-head. Mating cut-outs 59 formed in said top and bottom walls receive the wheel sections. Said hub 42 is held against displacement endwise to the rocker axis by face plates 53 (FIG. 4) rigidly secured to the cross-head and attached by pivot pins 52 to the hub. To serve a stop function limiting the rocker motion of the gripping shoe, ends of the hinge pin present chordal flats and receive a slide tit (see FIG. 7) in open- 6 end slots 49 provided in the two side walls 4S of the open-center cross-head.

The outermost hinge leaves 43A and 43B of the butts 43 are each prolonged inwardly and these prolongations are made integral with a four-sided cage 54. The square pocket which the cage presents faces inwardly. Pressing against the walls of said cage are free outer ends of four spring stacks 56 disposed longitudinal to the cross-head and arranged in pairs of two opposing stacks one pair flexing in a vertical plane and the other pair in a horizontal plane. A mounting block 57 anchors the inner ends of the spring stacks. Thus the upper and lower spring stacks yieldingly resist the swing motion of the shoe 27 about the center of the hinge pin 46 as an axis, while the front and rear spring stacks yieldingly resist the swing motion of the shoe about the center of the wheels 47 as an axis.

Each of the spring-stack .anchor blocks 57 is rigidly secured to a respective vertical cross-bar 58 which extends through vertically aligned holes in the top and.

bottom walls of the related cross-head and has its exposed ends pivotally attached to a related one of the two ends of the jacks 32, the jacks being thus wholly carried by the cross-bars. Said exposed ends of one of the two cross-bars also connect with one end of each of the two horizontal steering jacks 33. The other ends of the two jacks 33 connect with lugs 72 which are integral with the muff. Within the hollow center of the cross-head said cross-bars are engaged by set-scews 61, being pressed by the latter against the outer edge of said vertically aligned holes. Openings 62 are provided in the cross-heads to give access to these set-screws. Two set-screws 63 are also provided for holding each crossbar against endwise shifting, one to bear against the root portion of the upper spring stack and one against the root portion of the lower spring stack, and four additional set-screws 64, one for each free end portion of the four spring stacks, prescribe limits of outward motion therefor.

To guide the cross-heads in their slide movement within the mu, internal slippers (see FIG. 6) are fixed to the mutf and bear against the sides, top and bottom of the cross head.

To provide a universal attachment as between the after ends of the thrust jacks 37 and the gripper shoes,

4each shoe, above and below its connection with the related cross-head, has a Z-bar 68 rigidly secured to its inner side. A forwardly pointing arm 69 of this Z-bar lies in spaced paralleling relation to the shoe proper to produce a substantial fork. A horizontal wrist pin ,70 spans this fork, and straddling such pin and pivoted thereto by a vertical pin 71 is the after end of a related thrust jack 37. The areal compass of the spiked portion of the shoes 27 is very substantial, and such portion is ,desirably square in shape with the spikes located at the center and at each of the four corners. Wing prolongations to which the Z-bars 68 are attached extend vertically top and bottom beyond such spiked portion, -thus vplacing the axial lines of the thrust jacks 37 Well above and well below the slide axes of the cross-heads.

Proceeding now to a detailed description of the carriage 34, there is cut in the front and back walls of the mufr, at the mid-height and central to the length, aligned guideways 75 moderately elongated longitudinally of the muif. A beam 77 which admits to horizontal swing movement `is received through and projects beyond these guideways and is pivotally attached to the muff by a vertical pin 76 located on the median longitudinal line of the muff. Fabricated box sections 73 and 74 provide mountings for the pin. The two protruding ends 79 of the swing-beam are received for pivot motion in boxes 78, and these boxes are in turn received for vertical motion in a respective slide-way 82 provided by the carriage in each of the two side walls 80 and 81 of the latter.

Each of said side walls of the carriage, viewed in elevation, has an H configuration to produce the aforementioned re-entrant channel-forming openings which accommodate the jumbo bars 36A and 36B. Bearingslipper members 96 and 97 produce the slide journals for the bars. The vertical legs, designated 83, of said H-shaped walls of the carriage each carry a row of vertically spaced and inwardly facing pots 91. Compression springs 90 are housed in these rows of pots and function, the several springs in each row, as a set to springload a respective push-plate. Designated by 87 in respect of the two push-plates which are located at the front side and by 88 in respect to the two located at the back side, said push-plates bear against end portions of the mutf sides and by their spring-loading yieldingly resist movement of the muff about the center of the pin '76 as a swing axis from a normal position whereat the mulfs longitudinal median plane parallels the vertical longitudinal median plane of the carriage. Nutted rods 94 hook the push-plates at the top and bottom of the latter to preclude the push-plates from being pushed inwardly beyond said prescribed normal. T-bar spanners 86 at the upper and lower ends of each of the legs 83 rigidly connect the front and back side walls of the carriage. To make the described attachment to the mutf from the lower ends of the four vertical steering jacks 38, a respective transverse stirrup member 98 underlies the mutf at each of its two ends, being attached thereto by hangers 99. Laterally protruding ends of the stirrup member are each surmounted by a lug, and the steering jacks connect with these lugs. This and the top connection is one which gives universal motion, and which is to say pivoting about two transverse axes, one normal to the other.

From the foregoing .it will be seen that while thrust loads are passed back to the gripper shoes 40 directly from the head end of the machine, torque loads created as the rotary head performs its cutting action are carried by the machine frame members 36A and 36B back to the carriage 34. The vertical steering jacks 38 resist this transmitted torque, and pass the same through the muff 31 and cross-heads 30 into the side wall of the tunnel. Should the gripper shoes creep circumferentially of the tunnel by this torque load in consequence, say, of having taken their purchase against a faulty surface the carriage can be easily brought back to level by manipulation of the vertical steering jacks.

It is thought that the invention will have been clearly understood from the foregoing detailed description of y our now-preferred illustrated embodiment. Changes in the details of construction may be resorted to without departing from the spirit of the invention and it is accordingly our intention that no limitations be implied and that the hereto annexed claims be given the broadest interpretation to which the employed language fairly admits.

What we claim is:

1. In a tunnel-boring machine, a power-driven rotary cutting head, a supporting main frame having said head journal-mounted upon a front portion thereof and providing a rearwardly extending trunk portion fixedly associated with the main frame and presenting slide faces disposed parallel with the rotary axis of the head, a steering box providing a slide-way for said slide faces of the trunk constraining the trunk to travel along a guided linear path which is xed in relation to the steering box, anchor means located at each of the two sides of the steering box movable into and out of gripping engagement with the wall of a tunnel being bored, means supporting said steering box from the anchor means for governed adjusting movements permitting the line of said guided travel path to be altered while a cut is in progress between a normal position occupied when a straight section of tunnel is being bored and positions which are angled in selectively variable degrees with respect thereto within a range of given magnitude, the governed adjusting movements to which the steering box admits including lateral motion toward or from either anchor means, selectively, and power-operated means for making said governed adjusting movements and positively holding the steering box in the adjusted position to which it is moved.

2. A tunnel-boring machine according to claim 1 having strut-forming double-acting hydraulic jacks extending longitudinally of the tunnel with their rear ends attached to the anchor means and their front ends attached to the main frame, the cutting head being advanced within the tunnel by extension of said jacks, thrust forces resulting from said advance being passed through said jacks to the anchor means.

3. A tunnel-boring machine according to claim 2 in which the anchor means comprises two shoes located at diametrically opposite sides of the steering box, a pair ,of said jacks being provided for each of the shoes located one at one side and the other at the other side of `a plane occupied by both shoes and extending longitudinally of the tunnel being bored, the four jacks provided by said two pairs of jacks being individually operable.

4. A tunnel-boring machine according to claim 1 in which said governed adjusting movements to which the steering box admits also includes rolling motion about a vertical axis, the steering box being both rolled about said vertical axis and shifted in said lateral motion when placing said guided travel path along which the trunk slides in a position angular to its said normal position.

5. A tunnel-boring machine according to claim 4 in which the steering box is also mounted for vertical shifting movements.

6. A tunnel-boring machine according to claim 1 in which said governed adjusting movements to which the steering box admits also includes rolling motions about a vertical axis and about a transverse horizontal axis, the steering box being both rolled about either or both of said axes and shifted in said lateral motion when placing said guided travel along which the trunk slides in a position angular to its said normal position.

7. A tunnel-boring machine according to claim 6 in which the lateral shifting movement, the rolling movement about a vertical axis, and the rolling movement about a transverse horizontal axis are each performed by a respective set of double-acting hydraulic jacks.

8. A tunnel-boring machine according to claim 6 having means yieldingly opposing rolling movement of the steering box from said normal condition which it occupies when the machine is boring a straight length of tunnel.

9. A tunnel-boring machine according to claim 1 in which the anchor means are comprised of wall-engaging shoes mounted for opposing movements transversely of the tunnel along a coinciding axis, and having a double-acting hydraulic jack extending between and connected with the shoes for moving the shoes into and out of engagement with the tunnel wall.

10. A tunnel-boring machine according to claim 9 in which the connection between the shoes and said jack which moves the same into and out of engagement with the tunnel wall is one permitting the shoes to rock about two axes one a horizontal axis and the other a vertical axis in planes at right angles to the axis along which the shoes are moved into and out of said engagement.

11. In a tunnel-boring machine, an assembly of telescoping tubes adapted t0 extend transversely of the tunnel being bored and upon each of the two ends providing a respective gripping shoe adapted by telescopic extension to be brought into gripping engagement with the tunnel wall for anchoring the tube assembly, power means for extending and contracting said tube assembly,

a steering box adjustably mounted on said tube assembly for governed simple and compound rolling movements about a transverse horizontal axis, power-operated means for making said governed adjusting movements and positively holding the steering box in the adjusted position to which it is moved, a main frame adapted to extend longitudinally of the tunnel and intermediate its ends receiving support from the steering box for guided slide motion of the frame endwise to its length along an axis lixed with respect to the steering box, said frame having a cutting head mounted for rotation upon the front end about an axis paralleling the frames said guided axis of endwise slide motion, and jacks at the two sides of the machine connecting with the frame at a point spaced to the rear of the cutting head and extending rearwardly therefrom to the gripper shoes to function as struts for the front end of the frame, said strut-forming jacks being characterized in that the same can be extended or retracted at will either individually or collectively as one.

12. A tunnel-boring machine according to claim 11 in which the gripping shoes are so mounted upon the ends of the tube assembly that the same can rock about two axes one a horizontal axis extending transverse to the tube assembly and the other a vertical axis at right angles thereto.

13. A tunnel-boring machine as recited in claim 11 having shoes supported by the machine frame at the front end of the latter arranged to bear against and slide with respect to the tunnel wall and serving to stabilize the cutting head as the latter performs its cutting function.

14. A tunnel'boring machine according to claim 11 in Which the tube assembly comprises respective cross-heads located at each of the two sides of the machine and mounted for opposing slide motion in the two ends of a muli?, the gripping shoes being carried upon the outer ends of the cross-heads, the steering box receiving its mounting from the mut.

15. A tunnel-boring machine according to claim 14, spring-loaded means being provided yieldingly urging the steering box into a given normal position whereat the slide axis of the frame is disposed at right angles to the axial center of the muil.

16. In a tunnel-boring machine, a power-driven rotaml cutting head, a supporting main frame having said head journal-mounted upon a front portion thereof and to the rear of said journal providing a rigid trunk, the trunk presenting guide faces disposed parallel with the rotary axis of the cutting head, an anchor assembly including shoes arranged to be pressed outwardly into gripping engagement with the wall of the tunnel, trunkpositioning means providing for each of said guide faces a respective surface disposed longitudinal to the tunnel and over which `'the guide face slides, and operative interconnection between the anchor assembly and the trunkpositioning means permitting the slide surfaces of the latter to be set in selected adjusted positions shifted inwardly and outwardly in relation to the Walls of the tunnel so as to steer the head by constraining the head to travel a guided path.

References Cited by the Examiner UNTED STATES PATENTS 551,508 12/ 95 McKinlay 299-31 2,083,834 6/37 Galuppo. 3,061,287 10/62y Robbins. 3,061,288 10/ 62 Robbins.

FOREIGN PATENTS 852,537 10/ 60 Great Britain.

CHARLES E. OCONNELL, Primary Examiner.

BENJAMIN HERSH, Examiner. 

16. IN A TUNNEL-BORG MACHINE, A POWER-DRIVEN ROTARY CUTTING HEAS, A SUPPORTINF MAIN FRAME HAVUNG SAID HEAD JOURNAL-MOUNTED UPON A FRONT PORTION THEREOF AND TO THE REAR OF SAID JOURNAL PROVIDING A RIGID TRUNK, THE TRUNK PRESENTING GUIDE FACES DISPOSED PARALLEL WITH THE ROTARY AXIS OF THE CUTTING HEAD, AN ANCHOR ASSEMBLY INCLUDING SHOES ARRANGED TO BE PRESSED OUTWARDLY INTO GRIPPING ENGAGEMENT WITH THE WALL OF THE TUNNEL, TRUNKPOSITIONING MEANS PROVIDING FOR EACH OF SAID GUIDE FACES A RESPECTIVE SURFACE DISPOSED LONGITUDINAL TO THE TUNNEL AND A OVER WHICH THE GUIDE FACE SLIDES, AND OPERATIVE INTERCONNECTION BETWEEN THE ANCHOR ASSEMBLY AND THE TRUNKPOSITIONING MEANS PERMITTING THE SLIDE SURFACES OF THE LATTER TO BE SET IN SELECTED ADJUSTED POSITIONS SHIFTED INWARDLY AND OUTWARDLY IN RELATION TO THE WALLS OF THE TUNNEL SO AS TO STEER THE HEAD BY CONSTRAINING THE HEAD TO TRAVEL A GUIDED PATH. 